#include <stdio.h>

void fun1();
void fun2();
void fun3();
void usage();

int main(void)
{
	int i;
	
	printf("请选择1~3输入");
	scanf("%d",&i);

	switch(i) {
		case 1:
			fun1();
			break;
		case 2:
			fun2();
			break;
		case 3:
			fun3();
			break;
		default:
			usage();
			break;
	}
	
}

void fun1()
{
	printf("I am fun1\n");
}

void fun2()
{
	printf("I am fun2\n");
}

void fun3()
{
	printf("I am fun3\n");
}

void usage()
{
	printf("Please input 1~3\n");
}
